AIM: To construct a DNA vaccine against extracellular domains 1-3 of fetal liver kinase-1(flk-1), and to investigate its preventive and therapeutic effect against H22 cell in vivo. METHODS: Flk-1 DNA vaccine was produ...
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AIM: To construct a DNA vaccine against extracellular domains 1-3 of fetal liver kinase-1(flk-1), and to investigate its preventive and therapeutic effect against H22 cell in vivo. METHODS: Flk-1 DNA vaccine was produced by cloning extracellular domains 1-3 of flk-1 and by inserting the cloned gene into pcDNA3.1(+). Fifteen mice were divided into 3 groups and inoculated by vaccine, plasmid and saline respectively to detect specific T lymphocyte response. Thirty Mice were equally divided into preventive group and therapeutic group. Preventive group was further divided into V,P,andS subgroups, namely immunized by vaccine,pcDNA3.1(+) and saline, respectively, and attacked by H22 cell. Therapeutical group was divided into 3 subgroups of V,P and S, and attacked by H22, then treated with vaccine, pcDNA3.1(+) and saline, respectively. The tumor size, tumor weight, mice survival time and tumor latency period were compared within these groups. Furthermore,intratumoral microvessel density (MVD) was assessed by immunohistochemistry. RESULTS: DNA vaccine pcDNA3.1(+)flk-1-domains 1-3 was successfully constructed and could raise specific CTL activity. In the preventive group and therapeutic group,tumor latency period and survival time were significantly longer in vaccine subgroup than that in P and S subgroups (P<0.05);the tumor size, weight and MVD were significantly less in vaccine subgroup than that in P and S subgroups (P<0.05). The survival time of therapeutic vaccine subgroup was significantly shorter than that of preventive vaccine subgroup (P<0.05);the tumor size, and MVD of therapeutic vaccine subgroup were significantly greater than that of preventive vaccine subgroup (P<0.05).CONCLUSION: DNA vaccine against flk-1 domains 1-3 can stimulate potent specific CTL activity; and has distinctive prophylactic effect on tumor H22, and also can inhibit the tumor growth in vivo. This vaccine may be used as an adjuvant therapy because it is less effective on detectable tumor.
AIIVI: To investigate the reversal effect of neferine on multidrug resistance in human gastric carcinoma cell line. METHODS: Cells of a human gastric cancer cells line, SGC7901, and its vincristine (VCR) -resistant va...
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AIIVI: To investigate the reversal effect of neferine on multidrug resistance in human gastric carcinoma cell line. METHODS: Cells of a human gastric cancer cells line, SGC7901, and its vincristine (VCR) -resistant variant, SGC7901/VCR, were cultivated with or without neferine and/or VCR. The cytotoxic effect of VCR was evaluated by the MTT assay. Cell apoptosis induced by VCR was determined by flow cytometry(FCM). The expression of P-glycoprotein (P-gp) and a multidrug-resistance-associated protein (MRP) in cells was examined by immunofluorescence and FCM. RESULTS: Neferine at the concentration from 2.5 μmol/L to 10 μmol/L had no cytotoxicity to SGC7901 cells, and its variant SGC7901/VCR cells. The ICso of VCR against SGC7901 and SGC7901/VCR cells was 0.059 μg/mL and 2.32 μg/mL, respectively, indicating that SGC7901/VCR cells were 39 times more resistant to VCR than its parent SGC7 901 cells. After treatment with neferine at concentrations of 2.5, 5 and 10 μmol/L, the IC50 of VCR to SGC7901/VCR cell line decreased to 0.340, 0.128 and 0.053 μg/mL, respectively,thus, increased the chemosensitivity by 6.8-, 18.1- and 43.8-fold, respectively. SGC7901/VCR cells were apoptosis resistant to VCR. Neferine (2.5, 5 and 10 μmol/L) promoted the VCR-induced apoptosis of SGC7901/VCR cells in a dosedependent manner. The expressions of P-gp and MRP were strongly positive in SGC7901/VCR cells, which were significantly down-regulated after treatment with neferine (10 μmol/L)for 24 h. CONCLUSION: Neferine reverses multidrug resistance of human gastric carcinoma SGC7901/VCR cells, which may be associated with the down-regulations of P-gp and MRP expression in SGC701/VCR cells.
AIM: To observe the reversal effects of wide-type p53 gene on multi-drug resistance to 5-FU (LOVO/5-FU).METHODS: After treatment with Ad-p53, LOVO/5-FU sensitivity to 5-Fu was investigated using tetrazolium dye assay....
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AIM: To observe the reversal effects of wide-type p53 gene on multi-drug resistance to 5-FU (LOVO/5-FU).METHODS: After treatment with Ad-p53, LOVO/5-FU sensitivity to 5-Fu was investigated using tetrazolium dye assay. Multidrug resistance gene-1 (MDR1) gene expression was assayed by semi-quantitative reverse transcriptionpolymerase chain reaction and the expression of p53 protein was examined by Western ***: The reversal activity after treatment with wide type p53 gene was increased up to 4.982 fold at 48 h. The expression of MDR1 gene decreased significantly after treatment with wide-type p53 gene, and the expression of p53 protein lasted for about 5 d, with a peak at 48 h, and began to decrease at 72 ***: Wide-type p53 gene has a remarkable reversal activity for the high expression of MDR1 gene in colorectal cancers. The reversal effects seem to be in a time dependent manner. It might have good prospects in clinical application.
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